Field of the Invention
The present invention relates to prosthetic valves and methods for their implantation. More particularly, the present invention provides for prosthetic valve support structures configured for transcatheter delivery.
Background
Aortic valve replacement in patients with severe valve disease is a common surgical procedure. The replacement is conventionally performed by open heart surgery, in which the heart is usually arrested and the patient is placed on a heart bypass machine. Prostheses including prosthetic heart valves have been developed that are implanted using minimally invasive procedures such as transapical or percutaneous approaches. These methods involve compressing the prosthesis radially to reduce its diameter, inserting the prosthesis into a delivery tool, such as a catheter, and advancing the delivery tool to the correct anatomical position in the heart. Once properly positioned, the prosthesis is deployed by radial expansion within the native valve annulus.
Such a prosthesis can include a support structure to maintain the prosthetic heart valve in place. The inflow section of the prosthesis can be subject to radial interference from a body lumen, such as the left ventricular outflow tract (LVOT), that can exert circumferential radial pressure on the prosthesis. Such radial interference at an inflow section of the prosthesis can result in radial movement at an outflow section of the prosthesis. Such movement may be undesirable.
Moreover, a prosthesis can be subject to radial movement at an inflow section, due to, for example, valve function and cardiac contraction. Such radial movement can cause the diameter of the inflow section to experience cyclical contraction and expansion. Such contraction and expansion can subject the prosthesis to unnecessary fatigue.
Additionally, due to less than perfect conformance between the geometries of a patient's anatomy and the prosthesis, paravalvular leakage can occur. For example, a major course of leakage between a prosthesis and the LVOT wall is due to spaces created between scalloped leaflets called inter-leaflet triangles.
Accordingly, there is a need for a prosthesis that provides decoupled radial motion of the outflow section and the inflow section, and that better conforms to a patient's anatomy.
PCT Publication No. WO 05/002466 to Schwammenthal et al., which is incorporated herein by reference in its entirety, describes prosthetic devices for treating aortic stenosis.
PCT Publication No. WO 06/070372 to Schwammenthal et al., which is incorporated herein by reference in its entirety, describes a prosthetic device having a single flow field therethrough, adapted for implantation in a subject, and shaped so as to define a fluid inlet, and a diverging section, distal to the fluid inlet.
U.S. Patent Application Publication No. 2006/0149360 to Schwammenthal et al., which is incorporated herein by reference in its entirety, describes a prosthetic device including a valve-orifice attachment member attachable to a valve in a blood vessel and including a fluid inlet, and a diverging member that extends from the fluid inlet, the diverging member including a proximal end near the fluid inlet and a distal end distanced from the proximal end. A distal portion of the diverging member has a larger cross-sectional area for fluid flow therethrough than a proximal portion thereof.
U.S. Patent Application Publication No. 2006/0259136 to Nguyen et al., which is incorporated herein by reference, describes a heart valve prosthesis having a self-expanding multi-level frame that supports a valve body including a skirt and plurality of coapting leaflets. The frame transitions between a contracted delivery configuration that enables percutaneous transluminal delivery, and an expanded deployed configuration having an asymmetric hourglass shape. The valve body skirt and leaflets are constructed so that the center of coaptation can be selected to reduce horizontal forces applied to the commissures of the valve, and to efficiently distribute and transmit forces along the leaflets and to the frame. Alternatively, the valve body can be used as a surgically implantable replacement valve prosthesis.